六方与立方晶系界面匹配对硼化物与氮化物构成的纳米多层膜生长和力学性能的影响规律

The purpose of this project is to system study and reveal the influence of the interface matching rule of hexagonal crysals with cubic cystals on the growth of nanomultilayers. A series of superhard nanomultilayers consisting of hexagonal transition metal borides and cubic nitrides will be prepared by magnetron sputtering or ion beam assisted deposition. The interface matching rule as well as relation between deposition parameters, structure, and property will be investigated in detail. Our purpose will control interface matching and modulation by controlling the deposition parameters such as sputtering power, gas ratio, work pressure, bias, ion beam energy, deposition temperature, annealing and then control their growth regulation, and achieve optimal deposition process. The high-temperature stability and 30 GPa hardness above will be achieved with broad modulation period. The atomic mixture and diffusion, chemical bonding states, element compositions, defects will be measured using extensive measurements. The chemical states, density of states, the number and force of electrons in interfaces will be simulated and calculated using first-principles. Based on above investigations, the key role of interface matching and nanoscale multilayered modulation, as well as hard mechanism in this multilayer systems will be understood. The key is to summarize the interface matching rule of hexagonal crysals with cubic cystals, providing technical and theoretical support for research and development of this series of nanomultilayers.

目标是系统研究和揭示六方晶系和立方晶系界面匹配规律对纳米多层膜生长的影响规律。利用磁控溅射或离子束辅助沉积技术设计并合成由六方过渡金属硼化物为主与立方过渡金属氮化物构成的高硬纳米多层膜系列；系统研究该多层膜系列的界面匹配规律以及工艺、结构、性能三者之间的关系；通过控制溅射功率、气体比例、工作气压、偏压、轰击离子能量、沉积温度、退火等工艺，实现控制界面最佳匹配和调制结构，继而调控其生长规律的目的，使它们的硬度超过30 GPa，实现力学性能突变升高的调制周期变宽的预想，并在高温下保持稳定；利用多种微观分析技术获得界面原子混合、缺陷种类和浓度、扩散、化学态、界面能等信息，并结合第一性原理模拟计算界面处化学键、态密度、电子数量及受力变化，揭示界面匹配规律与机理和纳米多层调制在多层膜生长中的决定作用，并理解致硬机理；特别要揭示出六方和立方晶系界面匹配规律，为该系列纳米多层膜的研发提供理论和实验支持。

该项目系统研究和揭示了六方晶系和立方晶系界面匹配规律对纳米多层膜生长的影响规律。利用磁控溅射或离子束辅助沉积技术设计并合成了由六方过渡金属硼化物为主与立方过渡金属氮化物构成的高硬纳米多层膜系列。系统研究了该多层膜系列的界面匹配规律以及工艺、结构、性能三者之间的关系。通过控制溅射功率、气体比例、工作气压、偏压、轰击离子能量、沉积温度、退火等工艺，实现了控制界面最佳匹配和调制结构，继而调控其生长规律的目的。并使它们的硬度超过39 GPa，实现力学性能突变升高的调制周期变宽的预想。多层膜系统获得了很好的高温稳定性的同时，利用多种微观分析技术获得了界面原子混合、缺陷种类和浓度、扩散、化学态、界面能等信息，并结合第一性原理模拟计算界面处化学键、态密度、电子数量及受力变化，揭示了界面匹配规律与机理和纳米多层调制在多层膜生长中的决定作用。特别是发现了适用于多层体系的“二次外延”过程，使得六方和立方晶系界面匹配规律获得新的解释，在高温600摄氏度条件下，纳米硬度最高均超过了35 GPa，纳米多层膜的高温稳定性也初步得到验证。该项目为该系列纳米多层膜的研发提供了理论和实验支持。